HP-UX Reference (11i v1 05/09) - 3 Library Functions N-Z (vol 7)

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t_alloc(3) t_alloc(3)

NAME

t_alloc() - allocate a library structure

SYNOPSIS

#include <xti.h> /* for X/OPEN Transport Interface - XTI */

/* or */

#include <tiuser.h> /* for Transport Layer Interface - TLI */

char *t_alloc (fd, struct_type, fields);

int fd;

int struct_type;

int fields;

DESCRIPTION

The t_alloc() function dynamically allocates memory for the various transport function argument

structures as speciﬁed below. This function will allocate memory for the speciﬁed structure and will also

allocate memory for buffers referenced by the structure.

The structure to allocate is speciﬁed by struct_type and must be one of the following:

T_BIND struct t_bind

T_CALL struct t_call

T_OPTMGMT struct t_optmgmt

T_DIS struct t_discon

T_UNITDATA struct t_unitdata

T_UDERROR struct t_uderr

T_INFO struct t_info

where each of these structures may subsequently be used as an argument to one or more transport func-

tions.

Each of the above structures, except T_INFO, contains at least one ﬁeld of type struct netbuf

.For

each ﬁeld of this type, the user may specify that the buffer for that ﬁeld should be allocated as well. The

length of the buffer allocated will be equal to or greater than the appropriate size returned in the info argu-

ment of

t_open() or t_getinfo(). The relevant ﬁelds of the info argument are described in the fol-

lowing list. The ﬁelds argument speciﬁes which buffer to allocate, where the argument is the bitwise-OR of

any of the following:

T_ADDR The addr ﬁeld of the t_bind, t_call, t_unitdata ,ort_uderr structures.

T_OPT The opt ﬁeld of the t_optmgmt, t_call, t_unitdata ,ort_uderr structures.

T_UDATA The udata ﬁeld of the t_call, t_discon,ort_unitdata structures.

T_ALL All relevant ﬁelds of the given structure. Fields which are not supported by e tran-

sport provider speciﬁed by fd will not be allocated (info values are <= 0).

For each ﬁeld speciﬁed in ﬁelds, t_alloc() will allocate memory for the buffer associated with the ﬁeld,

and initialize the len ﬁeld to zero and the buf pointer and maxlen ﬁeld accordingly. Since the length of the

buffer allocated will be based on the same size information that is returned to the user on

t_open() or

t_getinfo() , fd must refer to the transport endpoint through which the newly allocated structure will

be passed. In this way the appropriate size information can be accessed. If the size value associated with

any speciﬁed ﬁeld is −1or−2 ( see t_open(3) or t_getinfo(3)), t_alloc() will be unable to determine the

size of the buffer to allocate and will fail, setting t_errno to [TSYSERR] and errno to [EINVAL]. For

any ﬁeld not speciﬁed in ﬁelds, buf will be set to a null pointer and maxlen will be set to zero.

Use of t_alloc() to allocate structures will help ensure the compatibility of user programs with future

releases of the transport interface functions.

Thread-Safeness

The t_alloc() function is safe to be called by multithreaded applications, and it is thread-safe for both

POSIX Threads and DCE User Threads. It has a cancellation point. It is neither async-cancel safe nor

async-signal safe. Finally, it is not fork-safe.

Valid States

All - apart from T_UNINIT

Section 3−−946 Hewlett-Packard Company − 1 − HP-UX 11i Version 1: September 2005